Analysis system for analyzing a sample on a test element

ABSTRACT

The invention relates to an analysis system for analyzing a sample on a test element. The system has an analysis unit for generating a signal as a function of an analyte contained in a sample, and a detection unit for detecting the signal. The analysis system further includes a test element holder into which the test element can be reversibly introduced and in which it can be positioned relative to the analysis unit and the detection unit. The test element contains at least one guide element, which is suitable for laterally guiding the test element, so that the test element in the test element holder is held and guided only on an outer region of the test element, and an inner region of the test element introduced into the test element holder remains free. The test element contains a sample application site in the inner region.

REFERENCE TO RELATED APPLICATIONS

The present application claims priority to German Patent Application No.10 2004 036 474.5, filed on Jul. 28, 2005, which is hereby incorporatedby reference in its entirety.

TECHNICAL FIELD

The present invention relates to an analysis system for analyzing asample on a test element.

BACKGROUND

In order to analyse samples, for example bodily fluids such as blood orurine, it is common to use analysis systems in which the samples to beanalyzed are located on a test element, and optionally interact in atest field with one or more reagents on the test element before they areanalyzed. The optical, in particular photometric, evaluation of testelements is one of the most commonly used methods for rapidlydetermining the concentration of analytes in samples. Photometricevaluations are widely used in the field of analysis, environmentalanalysis and above all in the field of medical diagnosis. Especially inthe field of blood glucose diagnosis from capillary blood, test elementswhich are photometrically evaluated are of great value.

There are various forms of test elements. Essentially square sheets,also referred to as slides, in the middle of which there is a multilayertest field are known, for example. Diagnostic test elements which are ofstrip-shaped design are referred to as test strips. Test elements aredescribed in the prior art, for example in the documents DE-A 197 53847, EP-A 0 821 233, EP-A 0 821 234 or WO 97/02487. The presentinvention relates to test elements of any shape, and in particularstrip-shaped elements.

Test elements in which a sample is applied to a sample application site,and is transported by means of capillary action to a detection zone(test field) separate from the sample application site, are known in theprior art. For example, DE 197 53 847 A1, published in English asCA2311496, which is hereby incorporated by reference in its entiretyrelates to such a test element. It describes an analytical test elementfor the determination of an analyte in a liquid. It contains an inertsupport, a detection element and a channel suitable for capillary liquidtransport, which has a sample application opening at one end and aventilation opening at the other end of the channel suitable forcapillary liquid transport. The channel suitable for capillary liquidtransport is formed at least partially by the support and the detectionelement, and extends in the capillary transport direction from thesample application opening at least as far as the detection element edgeclosest to the ventilation opening, a recess in a face which forms thechannel suitable for capillary liquid transport being located on thetest element edge forming the sample application element. The testelement edge forming the sample application opening is thus interruptedat least partially on one side, and the face opposite the recess isfree. The recess in a face forming the capillary channel on the edge ofthe test element is used to ensure that the sample liquid can enter thecapillary channel. This is achieved in that the sample drop on the testelement edge closest to the sample application opening, which isinterrupted by the recess, can be brought directly in contact with oneof the faces which form the inner surface of the capillary in theirextension. By suitable choice of the geometry and dimensions of therecess, the liquid drop is very likely to come in contact with theactive capillary zone and be readily sucked into the interior of thecapillary, regardless of the exact position of the dosing.

For the analytical study of a sample on a test element, test elementanalysis systems are known in the prior art which contain a test elementto position the test element in a measuring position, and a measurementand evaluation device for carrying out a measurement and determining ananalysis result based on this. WO 00/19185 A1, which is herebyincorporated by reference in its entirety, relates to a device for thephotometric evaluation of test elements, containing

-   -   an illumination unit having at least a first light source and a        second light source,    -   a frame for receiving a test element with a detection zone, so        that the detection zone is positioned opposite the illumination        unit,    -   a detection unit having at least one detector, which detects        light reflected by the detection zone or transmitted through the        detection zone,    -   a control unit, which activates the two light sources and        records the signal generated by the detection unit as a        detection signal, and    -   an evaluation unit, which evaluates the detection signals in        order to determine the analyte concentration contained in the        sample.

Known types of measuring apparatus have an opening, generally a slot,into which the test elements can be inserted. Guide elements ensure thata test element is inserted with the intended orientation. If the testelement is introduced manually into the apparatus, design features ofthe apparatus must be provided which guarantee the desired positioningof the test element. This is usually done by a restriction whichprevents insertion beyond a predetermined target position. Analysissystems which contain a storage container (magazine) with a multiplicityof test elements are furthermore known in the prior art. In this case,for example, a test element is transported from the storage container tothe measuring position by a slide or plunger, and is automaticallydiscarded from the analysis system after the measurement has beencarried out.

DE 199 02 601 A1, published in English as U.S. Pat. No. 6,475,436 (B1),discloses a device for extracting a consumable analytical medium, inparticular a test element, from a storage container which has one ormore chambers containing consumable media. The chambers respectivelyhave an extraction opening for extracting a consumable medium and aninsertion opening, opposite the extraction opening, for introducing aplunger to transport the consumable medium. The extraction opening andthe insertion opening are closed by a film in order to store theconsumable medium. The device comprises a plunger which can be moved bymeans of a drive unit in order to extract a consumable medium.

Discarding the consumable test elements entails a contamination orinfection risk since they are released without control into theenvironment and carry the rest of the sample material (for exampleblood, urine or interstitial fluid) on their surface. Hygienic handlingand disposal of the test elements could be ensured by transport backinto a storage magazine contained in the analysis system being used(re-magazining) or transport into a waste magazine intended for disposalof the test elements.

In the test element analysis systems known in the prior art, the testelement in the measuring position rests via at least a large fraction ofits lower side on a measuring apparatus surface in the analysis system.The lower side is pushed over the measuring apparatus surface duringtransport of the test element into and out of the measuring position.The test element is in this case guided by means of lateral guide faceswhich are perpendicular to the measuring apparatus surface. In a systemfor photometrically evaluating the test element, the measuring apparatussurface usually contains an optical window, below which the optics arelocated. Resting the test element via a large fraction of its lower sideon the measuring apparatus surface has the disadvantage that a liquidsample applied to the test element, in the vicinity of one of its sideedges, can stain the measuring apparatus surface. For example, a part ofthe liquid sample could be drawn by capillary forces between the testelement and the measuring apparatus surface, so that a further regionincluding the optical window is wetted with the sample. Such stainingoccurs in particular when the test element is being drawn back over themeasuring apparatus surface into the magazine after the measurement hasbeen carried out (re-magazining). In this case, any sample adhering tothe test element edge used for the sample application will be wiped overthe measuring apparatus surface.

The optical window of the analysis systems known in the prior art has tobe sunk into the measuring apparatus surface in order to protect itagainst damage due to friction by the test element.

SUMMARY

The analysis system of the present invention comprises an analysis unitfor generating a signal as a function of an analyte contained in asample, and a detection unit for detecting the signal, and a testelement holder into which the test element can be reversibly introducedand in which it can be positioned relative to the analysis unit and thedetection unit. The test element contains at least one guide elementwhich is suitable for laterally guiding the test element, so that thetest element in the test element holder is held and guided only on anouter region of the test element, and an inner region of the testelement introduced into the test element holder remains free. The testelement contains a sample application site in the inner region.

Further, a method of analyzing the glucose content in a sample isprovided in accordance with the invention. The method comprises thesteps of providing a test element having an outer region and an innerregion, the inner region containing a sample application site, providingan analysis system comprising an analysis unit for generating a signalas a function of glucose contained in the sample, a detection unit fordetecting the signal, and a test element holder into which the testelement can be reversibly introduced and in which the test element canbe positioned relative to the analysis unit and the detection unit, thetest element holder containing at least one guide element which issuitable for laterally guiding the test element, so that the testelement in the test element holder is held and guided only on the outerregion of the test element, and the inner region of the test elementintroduced into the test element holder remains free, applying a sampleto the sample application site of test element, introducing the teststrip into the test element holder so that the test element is held onthe outer region, generating a signal as a function of the glucosecontained in the sample, and detecting the signal.

Still further, an apparatus for holding a test element used in ananalysis system is provided. The test element has an outer region and aninner region, the inner region containing a sample application site. Theapparatus comprises a body being formed to include a guide element sizedfor laterally guiding the test element so that the test element in thebody is held and guided only on the outer region of the test element,and the inner region of the test element introduced into the testelement holder remains free, the guide element including spaced-apartsupport faces, on which the test element rests in its outer regions, andan optical window spaced-apart from the guide element.

In an embodiment of the invention, the analysis unit and the detectionunit can be parts of measuring optics, which are used to photometricallyevaluate the test element. A light source and optics are for exampleused as the analysis unit for photoelectric evaluation, and for examplea photodetector which detects the light reflected by the test fieldsupplied with the sample or transmitted through the test field (opticalsignal) is used as the detection unit. Such a detection signal isevaluated in the known way in order to determine the analyteconcentration.

In an embodiment of the present invention, the guide element containssupport faces, on which the test element rests via bearing faces in itsouter region, and guide faces along which side faces of the test elementare guided. In this context, care should be taken that sufficientclearance still remains between the slue faces of the test element andthe guide faces, so that the test element can be moved in the guideelement with minimal force exertion and so as to maintain a low level ofwear (for example, abrasion of the test element or notching in the guidewalls).

In an embodiment of the present invention, the guide faces are arrangedobliquely with respect to the side faces of the test element. The effectachieved by this is that a test element does not touch the guide facesover the entire side faces when it is being introduced into the guideelement, but is displaced along the guide faces via one edge. This isparticularly for test elements which are made of different layersadhesively bonded together. Such a test element is described, forexample, in DE 199 12 365 A1 published in English as U.S. Pat. No.6,881,378 (B1), which is hereby incorporated by reference in itsentirety. Because of the obliquity of the guide faces, they are notstained by any adhesive which may be encountered on the side faces ofthe test element.

The bearing faces on which the test element rests in its outer regionhave a width of from 0.1 mm to 1 mm, particularly from 0.3 mm to 0.5 mm.With a correspondingly small clearance, they are therefore wide enoughto prevent the test element from undesirably falling out of the guideelement.

In an embodiment of the present invention, the guide element containstwo mutually opposite grooves, into which the test element can beinserted via its outer region. In such a guide element, the test elementis introduced by a sliding movement into two grooves, one each on theleft-hand and right-hand sides of the test element. The grooves enclosethe edges and side faces of the test element so that the test elementcannot fall out of the guide element neither upwards nor downwards(closed guiding).

In an embodiment of the present invention, the guide element is arrangedabove the analysis unit and/or the detection unit in the analysissystem. For the photometric evaluation, for example, the measuringoptics (including the light source and photodetector) are arranged at aslight distance below the guide element in the analysis system. It isnevertheless possible to arrange the analysis unit above the guideelement and the detection unit below the guide element, or vice versa.

In an embodiment of an analysis system according to the invention, theguide element is arranged so that a test element introduced into theguide element is at a distance of at least 1 mm from the analysis unitand the detection unit in any position. This distance ensures that theliquid sample cannot be drawn in by capillary forces between the testelement and the analysis unit or the detection unit, and stain it.Furthermore, for example, an optical window no longer has to be sunkinto the measuring apparatus surface since the distance protects it frommechanical stress, which simplifies the design of the analysis system.

In an embodiment of the present invention, the test element holdercontains a stop, against which a test element abuts when it is beingintroduced into the guide element, so that a defined position of thetest element in the test element holder is achieved. The stopestablishes how far the test element should be introduced into the guideelement.

In an embodiment of the present invention, the test element comprises asample application site at one end in the inner region, the test elementbeing tapered in the region of the sample application site. The taperingmay, for example, be in the form of a shoulder or indentation. This testelement can be wetted with the sample only over the width of the taperedend in its inner region, and not over the full width. The outer regionof the test element, in which it is held and guided, thus remains freeof the sample, and staining of the guide element which is in contactwith the outer region is substantially avoided. The tapered region ofthe test element, with the sample application site, may furthermoreprotrude out of the test element holder in order to allow sampleapplication on the outside. In particular, the guide element may have astop on which the wide (normal) region of the test element, which isnext to the tapered region, abuts as soon as it has been introduced overa sufficient distance into the guide element.

In an embodiment of the present invention, the analysis system alsocomprises a storage container for a multiplicity of test elements, intowhich the test elements are transported back from the test elementholder after use. As such, the used test elements are handled anddisposed of hygienically. The analysis system according to the inventionin this case has a transport device for automatically extracting a testelement from the storage container, for automatically transporting thetest element into the test element holder and for automaticallytransporting the test element back into the storage container after use.The transport device comprises, for example, a plunger, a hook or aclip, which can couple to a test element and subsequently transport itinto a desired position in the analysis system. In an embodiment of thepresent invention, the test element has a test field where the sample isanalyzed, and which is positioned in the inner region of the testelement. For the qualitative or quantitative analytical determination ofcomponents of the liquid sample, in particular bodily fluids, reagentsare embedded in the test field. The test field is brought in contactwith the sample and, if a target analyte is present, the reactionbetween the liquid sample and the reagents leads to a detectable signal,for example a colour change, which can be detected with the aid of theanalysis unit and the detection unit. In the present invention, the testelement contains a capillary for delivering the sample to the testfield.

In one embodiment of the present invention, the test element holder ismade of at least two parts, with a test element introduced into the testelement holder resting in its outer region on a lower part of the testelement holder and with a separate upper part of the test element holderresting on the test element in its outer region. In the absence of atest element, the two parts are placed loosely on one another and arelaterally secured against displacement. When a test element isintroduced into the guide element between the two parts of the testelement holder, the two parts are pressed apart from each other by thetest element. The test element therefore fits tightly into the guideelement and is held in position by the upper part, which rests on itsouter region, for example when the sample application and/or measuringposition has been reached.

At least one pressure spring, which exerts a force on the upper part inthe direction of the lower part of the test element holder, is arrangedon the upper part of the test element holder. The spring forceadditionally holds the test element in position.

In the present invention, the guide element may have a ramp- orfunnel-shaped introduction opening on the side where a test element isintroduced into the test element holder. The ramp- or funnel-shapedintroduction opening facilitates the introduction of a test element intothe guide element.

In one embodiment of the present invention, the guide element is shapedso that it causes a defined deformation of a test element introducedinto the test element holder, in order to fix it during use. Forexample, the guide element may be bent in the longitudinal direction sothat a test element is deformed in a defined way in the longitudinaldirection when it is being introduced into the guide element, and isunder a flexural stress in the measuring position. This ensures thedefined distance of the test field from the measurement unit comprisingthe analysis unit and the detection unit. Likewise, for example, theguide element designed as two grooves may be inclined with respect tothe introduction plane of the test element so that the test element inthe guide element is deformed in a defined way in the transversedirection. This likewise fixes the test element in the test elementholder.

These and other features of the present invention will be more fullyunderstood from the following detailed description of the inventiontaken together with the accompanying claims. It is noted that the scopeof the claims is defined by the recitations therein and not by thespecific discussion of the features set forth in he present description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail below with reference tothe drawings, in which:

FIG. 1A shows the introduction of a test element into a guide element ofan analysis system in the prior art,

FIG. 1B shows the sample application on a test element in a guideelement of an analysis system in the prior art,

FIG. 1C shows the extraction of a test element after a measurement froma guide element of an analysis system in the prior art,

FIG. 2A shows the manual handling procedure for a test element in ananalysis system of the prior art,

FIG. 2B shows the automatic transport procedure for a test element in ananalysis system of the prior art,

FIG. 3A shows the schematic representation of a detail of an analysissystem according to the invention, into which a test element isintroduced,

FIG. 3B shows the sample application on a test element in a guideelement of an analysis system according to the invention,

FIG. 3C shows the extraction of a test element after a measurement froma guide element of an analysis system according to the invention,

FIG. 4 shows a test element with tapering in the region of the sampleapplication site,

FIG. 5 shows a multi-part test element holder with pressure springs inan analysis system according to the invention, and

FIG. 6 shows a multi-part test element holder with oblique guide faces.

FIG. 7 shows the schematic representation of a detail of an analysissystem according to the invention, into which a test element isintroduced, and a diagrammatic view of an analysis unit and a detectionunit that are parts of measuring optics which are used tophotometrically evaluate the test element.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1A schematically shows the introduction of a test element into aguide element of an analysis system in the prior art.

In this case, the guide element 1 is a sort of open trough with abearing face 2 and side walls 3. In the bearing face 2, there is anoptical window 4 (symbolized by the circle) below which measuring optics(not shown) are arranged for photometrically evaluating the test element5. A test element 5 is introduced into the guide element 1 in theintroduction direction 6, while sliding with its full width via itslower side 7 over the bearing face 2. It is guided during introductionby the side walls 3, along which the side faces 11 of the test element 5slide. In the sample application position 8, the test element 5 restsextensively on the bearing face 2. The test element 5 protrudes beyondthe bearing face 2 via its end 9, which contains the sample applicationsite 10.

This design of the guide element 1 as represented in FIG. 1A, in whichthe test element 5 guided only laterally rests flat via the lower side7, is configured so that after the measurement (and the sampleapplication associated with it) the test element is not guided throughthe guide element 1 via the end to which the sample has been applied.This movement does, however, take place in an analysis system with are-magazining function. This will be demonstrated in FIGS. 1B and 1C.

FIG. 1B shows the sample application on a test element in a guideelement of an analysis system in the prior art.

The test element 5 is displaced into the sample application position 8while being guided by the guide element 1, as represented in FIG. 1A. Inorder to apply the sample 12, for example blood, the test element 5protrudes slightly from the analysis system in this position. A sample12 is applied onto the test element 5 at the sample application site 10.For this, the end 9 of the test element 5 is dipped slightly into thesample 12 so that it is wetted with the liquid sample 12 on its upperside 13 and its lower side 7.

FIG. 1C shows the extraction of a test element after a measurement froma guide element of an analysis system in the prior art.

If, after the measurement, the test element 5 is drawn back counter tothe introduction direction 6 (for example to re-magazine the testelement 5) from the sample application position 8 through the guideelement 1, then drops of the sample 12 adhering to the end 9 of the testelement 5 will be wiped off on the edge 14 of the guide element 1. Bycapillary forces, sample material will be drawn into the gap between thetest element 5 and the bearing face 2, and will be further distributedover the bearing face 2 by the extraction of the test element 5 over it.This leads to contamination or staining 15 of a wide region of thebearing face 2, including the optical window 4, by the sample material.The optical window 4 of the guide element 1 of an analysis system in theprior art, as shown in FIGS. 1A to 1C, needs to be sunk into the bearingface 2 for the test element 5, in order to protect it against damage dueto friction by the test element 5 during the introduction and theextraction of the test element 5 from the guide element 1.

FIGS. 2A and 2B demonstrate how test elements in the prior art arehandled manually or automatically. FIG. 2A shows the manual handlingprocedure for a test element in an analysis system of the prior art.

In manually operated analysis systems, the test element 5 is pushed intothe analysis system by the user in the introduction direction 6, intothe guide element 1 and over the optical window 4. In the sampleapplication position 8, a sample 12 is put onto the sample applicationsite 10 and the measurement is subsequently carried out. After themeasurement, the test element 5 is extracted from the analysis system bythe operator. The extraction is carried out in the extraction direction16, which is opposite to the introduction direction 6. The edge 17 ofthe test element 5, which is wetted with the sample 12, thus nevertouches the bearing face 2 and the optical window 4, so that staining isavoided. With such an analysis system in the prior art, extraction inthe same direction as the introduction direction 6 is not intended andwould lead to staining of the bearing face 2, as described withreference to FIG. 1C.

FIG. 2B shows the automatic transport procedure for a test element in ananalysis system of the prior art.

In automatically operated analysis systems of the prior art, the testelement 5 is pushed from a storage magazine 18 (for example by aplunger, not shown) in the introduction direction 6 into the guideelement 1. In the sample application position 8, a sample 12 is appliedto the test element 5 at the sample application site 10, and ameasurement is carried out. After the measurement, the test element 5 isejected (for example by the plunger) from the guide element 1 in thesame direction as the introduction direction 6. The edge 17 of the testelement 5, which is wetted with the sample 12, therefore does not touchthe bearing face 2 or the optical window 4, so that staining by thesample 12 is avoided. With such an analysis system in the prior art,extraction of the test element after the measurement in the oppositedirection to the introduction direction 6 (for example to put it backinto the storage magazine 18) is not intended and would lead to stainingof the bearing face 2, as described with reference to FIG. 1C.

FIG. 3A shows the schematic representation of a detail of an analysissystem according to the invention, into which a test element isintroduced. The analysis system of the present invention is intended toavoid staining of surfaces in the analysis system by the sample when atest element is being re-magazined after the measurement. The inventionfurthermore relates to the use of the analysis so that a test elementintroduced into the guide element will be positioned relative to theanalysis unit and the detection unit. Precise positioning of the testfield relative to the measuring optics is necessary in order to be ableto carry out an exact photometric evaluation, for example. As shown inFIG. 7, the analysis unit 52 and the detection unit 54 are arranged inthe analysis system 50. They are arranged e.g. below the optical window4, which is shown in FIG. 3A.

In an embodiment of the present invention, the test element holderfulfils not only the function of guiding a test element as it isintroduced, but also of holding it so that it remains in the measuringposition during the measurement. The test element can be introducedreversibly into the test element holder, so that it can be removed fromthe test element holder after the measurement in the opposite directionto the introduction direction.

The test elements used in the analysis system according to the inventioncan be test strips in which a liquid sample, in particular blood, urineor interstitial fluid, is transported from the sample application siteto the test field by means of capillary action. A channel suitable forcapillary liquid transport usually has an entry opening and aventilation opening. In an embodiment of the present invention, theentry opening is arranged in the vicinity of the sample applicationsite, i.e. in the inner region of the test element. The ventilationopening in the present invention is likewise arranged in the innerregion of the test element, so that any sample liquid accidentallyemerging from the ventilation opening cannot cause contamination of thetest element holder according to the invention.

The test element 5 is introduced into the guide element 20 in theintroduction direction 6. The guide element 20 is arranged above theoptical window 4 covering the analysis and detection units in theanalysis system. A test element 5 introduced into the guide element 20is at a distance of at least 1 mm from the analysis unit and thedetection unit in any position. This distance ensures that no samplematerial can be drawn from the sample application site 10 of the testelement 5 by capillary forces into the gap between the test element 5and the optical window 4. system according to the invention foranalyzing the glucose content in blood on a strip-shaped test element.

The analysis system according to the invention contains an analysis unitand a detection unit for photometric analysis, both of which arearranged (this cannot be seen in FIG. 3A, but can be seendiagrammatically, a non-limiting example of which is shown as analysisunit 52 and detection unit 54 in FIG. 7) below an optical window 4. Theanalysis system comprises a test element holder 19 into which the testelement 5 can be reversibly introduced, and in which it can bepositioned relative to the analysis and detection units arranged belowthe optical window 4. The test element 19 contains a guide element 20which is suitable for laterally guiding the test element 5. The guideelement 20 comprises two mutually opposite grooves 21, 22, into whichthe test element 5 can be inserted in its outer region 23. The testelement 5 is then held and guided in the test element holder 19 only inits outer region 23, and an inner region 24 of the test element 5introduced into the test element holder 19 remains free. The first andsecond grooves 21, 22 enclose the outer region 23 of the test element 5which has been introduced, so that it cannot fall out of the guideelement 20 either upwards or downwards (closed guiding). The guideelement 20 has support faces 25, on which the test element 5 can restvia bearing faces in its outer region 23, and guide faces 26 along whichthe test element 5 is guided during transport. During introduction,enough clearance is left around the outer region 23 of the test element5 so that the test element 5 can be moved with minor force exertion inthe guide element 20, and so as to maintain a low level of wear both forthe test element 5 and for the guide element 20. The support faces 25have a width b of between 0.1 mm and 1 mm.

Staining of the analysis system by the sample is avoided in the presentinvention since the test element is guided and held only in an outerregion, and an inner region of the test element introduced into the testelement holder remains free. In this context, the term inner region isparticularly intended to mean the central part of the two surfaces ofthe test element. The sample application site, where the sample is putonto the test element, is located in the inner region of the testelement so that it does not come in contact with the test element holderand cannot become contaminated by the sample. The guide element isarranged in the analysis system

The test element holder 19 may contain a stop (not shown). For example,one end 27 of the grooves 21, 22 may be closed and thus act as a stop.When inserted into the guide element 20, a test element 5 then abutsagainst the stop as soon as it has reached its sample applicationposition. Such a stop may also be used for test elements 5 which areintended to protrude from the analysis system for the sample applicationif the test elements 5 have a corresponding shape, in particular if theyare tapered in the region of the sample application site, for example inthe form of a shoulder or an indentation. The guide element 20 mayfurthermore contain position switches (not shown) which allow the testelement 5 to be positioned accurately.

In the test element holder 19, the guide element 20 may be configured sothat the test element 5 is fixed in particular positions by friction orby integrated holding clips or pressure springs (not shown), especiallyin the sample application or measuring position. Alternatively or inaddition, it is possible to fix the test element 5 with the aid of thedrive element (plunger, hook, clip, etc.) which is used for transportingthe test element 5 automatically into the analysis system according tothe invention.

FIG. 3B shows the sample application on a test element in a guideelement of an analysis system according to the invention.

The test element is located in the sample application position 8, wherethe sample 12 is put onto the sample application site 10 of the testelement 5. The subsequent measurement may likewise take place in thesample application position 8, or it may be carried out in a specialmeasuring position in the analysis system.

FIG. 3C shows the extraction of a test element after a measurement froma guide element of an analysis system according to the invention.

After the measurement procedure, the test element 5 is extracted fromthe test element holder 19 through the guide element 20, and optionallystored (re-magazining) in a storage magazine (not shown). The innerregion 24 of the test element 5, which is wetted with the samplematerial in the vicinity of the sample application site 10, is in thiscase guided through the test element holder at a secure distance fromthe optical window 4 and the grooves 21, 22. Surplus sample material,which would cause staining of the interior of the analysis system,cannot therefore become wiped off. The optical window 4 is furthermorenot mechanically stressed by the test element as it is being displaced,so that it does not have to be sunk and the design of the analysissystem is thereby simplified. The measuring optics present below theoptical window 4 are adapted in terms of their distance from the testelement 5.

FIG. 4 shows a test element with tapering in the region of the sampleapplication site.

As a further measure against wetting of the test element 5 by the sample12 over its full width, and against possible concomitant staining of theguide element of the analysis system according to the invention by thesample material, the test element is tapered at one end 28 in the regionof the sample application site 10. The tapering 29 has the shape of anindentation which is selected so that with maximum spreading of thesample 12, the wide region 30 of the test element 5 is not wetted by thesample 12. This prevents pollution of the guide element 20, which comesin contact only with the outer region 23 of the test element 5.

FIG. 5 shows a multi-part test element holder 19 with pressure springsin an analysis system according to the invention.

The test element holder 19 comprises a lower part 31 and an upper part32, which lie on top of one another and are laterally secured againstdisplacement. Two pressure springs 33 engage on the upper part 32, andthey exert a force on the upper part 32 in the direction of the lowerpart 31. A test element 5 can be inserted into a guide element 20 in theintroduction direction 6, between the lower part 31 and the upper part32, the two parts 31, 32 are then pressed apart from each other by thistest element 5 and the test element 5 fits tightly into the guideelement 20. The test element 5 can be additionally fixed in a desiredposition in the guide element 20 by the pressure of the pressure springs33.

On the side where a test element 5 is introduced into the test elementholder 19 (the rear side not shown in FIG. 5), the test element holder19 has a ramp- of funnel-shaped introduction opening, through which thetest element 5 can be pushed into the guide element 20. Thisintroduction opening facilitates the introduction of a test element 5which is taller than the inner height of the guide element 20 beforeintroduction of the test element 5.

FIG. 6 shows a multi-part test element holder with oblique guide faces.

The test element holder 19 comprises a lower part 31 and an upper part32, between which a test element 5 can be inserted into a guide element20. The guide element 20 has support faces 25, on which the test element5 rests via bearing faces in its outer region 23, and guide faces 26along which the side faces 34 of the test element are guided. The guidefaces 26 are in this case arranged obliquely with respect to the sidefaces 34 of the test element 5, in order to avoid staining of the guidefaces 26 by the side faces 34 (for example due the adhesive adhering onthem).

Having described the invention in detail and by reference to specificembodiments thereof, it will be apparent that modification andvariations are possible without departing from the scope of theinvention defined in the appended claims. More specifically, althoughsome aspects of the present invention are identified herein, it iscontemplated that the present invention is not necessarily limed tothese one aspects of the invention.

1. Analysis system for analyzing a sample on a test element having anouter region and an inner region, the inner region containing a sampleapplication site, the system comprising an analysis unit for generatinga signal as a function of an analyte contained in the sample, and adetection unit for detecting the signal, characterized by a test elementholder into which the test element can be reversibly introduced and inwhich the test element can be positioned relative to the analysis unitand the detection unit, the test element holder containing at least oneguide element which is suitable for laterally guiding the test element,so that the test element in the test element holder is held and guidedonly on the outer region of the test element, and the inner region ofthe test element introduced into the test element holder remains free.2. Analysis system of claim 1, wherein the guide element containssupport faces, on which the test element rests via bearing faces in itsouter region, and guide faces along which side faces of the test elementare guided.
 3. Analysis system of claim 2 wherein the guide faces arearranged obliquely with respect to the side faces of the test element.4. Analysis system of claim 2 wherein the support faces have a width offrom 0.1 mm to 1 mm.
 5. Analysis system of claim 1 wherein the guideelement contains two mutually opposite grooves, into which the testelement can be inserted via its outer region.
 6. Analysis system ofclaim 1 wherein the analysis unit and the detection unit are parts ofmeasuring optics which are used to photometrically evaluate the testelement.
 7. Analysis system of claim 1 wherein the guide element isarranged above the analysis unit and/or the detection unit in theanalysis system.
 8. Analysis system of claim 1 wherein the guide elementis arranged so that a test element introduced into the guide element isat a distance of at least 1 mm from the analysis unit and the detectionunit in any position.
 9. Analysis system of claim 1 wherein the testelement holder has a stop, against which a test element abuts when it isbeing introduced into the guide element as soon as a defined position ofthe test element in the test element holder is reached.
 10. Analysissystem of claim 1 wherein the test element comprises a sampleapplication site at one end in the inner region, the test element beingtapered in the region of the sample application site.
 11. Analysissystem of claim 1 further comprising a storage container for amultiplicity of test elements, into which the test elements aretransported back from the test element holder after use.
 12. Analysissystem of claim 11 further comprising a transport device formed toautomatically extract a test element from the storage container, toautomatically transport the test element into the test element holderand to automatically transport the test element back into the storagecontainer after use.
 13. Analysis system of claim 1 wherein the testelement has a test field where the sample is analyzed, which ispositioned in the inner region of the test element.
 14. Analysis systemof claim 13 wherein the test element contains a capillary for deliveringthe sample to the test field.
 15. Analysis system of claim 1 wherein thetest element holder is made of at least two parts, with the test elementintroduced into the test element holder resting in its outer region on alower part of the test element holder and with a separate upper part ofthe test element holder resting on the test element in its outer region.16. Analysis system of claim 15 wherein at least one pressure spring,which exerts a force on the upper part in the direction of the lowerpart of the test element holder, is arranged on the upper part of thetest element holder.
 17. Analysis system of claim 1 wherein the guideelement has a ramp- or funnel-shaped introduction opening on the sidewhere the test element is introduced into the test element holder. 18.Analysis system of claim 1 wherein the guide element is shaped so thatit causes a defined deformation of the test element as it is beingintroduced into the test element holder, in order to fix it during use.19. Method of analyzing the glucose content in a sample, the methodcomprising the steps of providing a test element having an outer regionand an inner region, the inner region containing a sample applicationsite, providing an analysis system comprising an analysis unit forgenerating a signal as a function of glucose contained in the sample, adetection unit for detecting the signal, and a test element holder intowhich the test element can be reversibly introduced and in which thetest element can be positioned relative to the analysis unit and thedetection unit, the test element holder containing at least one guideelement which is suitable for laterally guiding the test element, sothat the test element in the test element holder is held and guided onlyon the outer region of the test element, and the inner region of thetest element introduced into the test element holder remains free,applying a sample to the sample application site of test element,introducing the test strip into the test element holder so that the testelement is held on the outer region, generating a signal as a functionof the glucose contained in the sample, and detecting the signal.
 20. Anapparatus for holding a test element used in an analysis system, thetest element having an outer region and an inner region, the innerregion containing a sample application site, the apparatus comprising: abody being formed to include a guide element sized for laterally guidingthe test element so that the test element in the body is held and guidedonly on the outer region of the test element, and the inner region ofthe test element introduced into the test element holder remains free,the guide element including spaced-apart support faces, on which thetest element rests in its outer regions, and an optical windowspaced-apart from the guide element.
 21. Apparatus of claim 20 whereinthe guide element contains guide faces along which side faces of thetest element are guided.
 22. Apparatus of claim 21 wherein the guidefaces are arranged obliquely with respect to the side faces of the testelement.
 23. Apparatus of claim 20 wherein the support faces have awidth of from 0.1 mm to 1 mm.
 24. Apparatus of claim 20 wherein theguide element contains two mutually opposite grooves, into which thetest element can be inserted via its outer region.
 25. Apparatus ofclaim 20 wherein the test element holder has a stop, against which atest element abuts when it is being introduced into the guide element assoon as a defined position of the test element in the test elementholder is reached.
 26. Apparatus of claim 20 wherein the test elementholder is made of at least two parts, with the test element introducedinto the test element holder resting in its outer region on a lower partof the test element holder and with a separate upper part of the testelement holder resting on the test element in its outer region. 27.Apparatus of claim 26 wherein at least one pressure spring, which exertsa force on the upper part in the direction of the lower part of the testelement holder, is arranged on the upper part of the test elementholder.
 28. Apparatus of claim 20 wherein the guide element has a ramp-or funnel-shaped introduction opening on the side where the test elementis introduced into the test element holder.
 29. Apparatus of claim 20wherein the guide element is shaped so that it causes a defineddeformation of the test element as it is being introduced into the testelement holder, in order to fix it during use.